This project proposed to investigate several aspects of the involvement of birds in natural cycles of arboviruses. The most important was to determine the biological capacity of migratory birds to have acted as intercontinental carriers of the equine virulent strain of VE virus into Central America in 1969. During April and early May periods of 1973 to 1976, migratory birds were captured alive at sites on the Pacific lowlands of Guatemala near the epicenter of the explosive 1969 epizootic and epidemic of Venezuelan encephalitis (VE) virus and were inoculated with VE virus. All species that have been tested have become viremic, some, especially highly migratory shorebirds, have developed rather high levels of viremia, sufficient even by current unsophisticated knowledge to infect vector species of mosquitoes. BIBLIOGRAPHIC REFERENCE: R.W. Dickerman, C.M. Bonacorsa and W.F. Scherer. Viremia in young herons and ibis infected with Venezuelan encephalitis virus. The American Journal of Epidemiology (Nov. or Dec. 1976), in press.